Apparatus for pumping alpha plurality of oil wells



Feb- 2, 1932- w A. GAMMACK ET AL APPARATUS FOR PUMPING A P LURALITY OF OIL WELLS 4 sheets-sheet 1 Original Filed July l1. 1927 N MSN Feb. 2, 1932. wl A, GAMMACK ETAL 1,843,276.

APPARATUS FOR PUMPING A PLURALITY OF OIL WELLS Original Filed July 1l, 1927 4 Sheets-Sheet 2 f/vl/E/v Toes:

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APPARATUS FOR PUMPIN'G A PLURALITY oF oIL WELLS W. A. GAMMACK* ET AL 4 sheets-Sheet .5 il@ w w 1.. l l y i..WX m d 5. n. .n W 0 WV un.. m ffl/1% Z 7 n 7 /Nz/E/v Toes:

Fell 2, 1932. W. A. .GAMMACK yET AL APPARATUS FOR PUMPING A PLURALITY OF OIL WELLS original Filed Julyv 11-.

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original appuoation mea my 11, 1927, sei-m1 m. 204,999. mviaea and this aiipucation meavruly 5,

Patented F eb. 2, 1932 UNITED STATES PATENToFFIcE WILLIAM A. GAMMACK AND DONALD G. KNOX, OF LOS ANGELES, CALIFORNIA, AS-

'SIGN'ORS, BY MIBNE ASSIGNMENTS, TO JORDAN-8c TAYLOR, INC., OF'LOS ANGELES,

CALIFORN'IA,.A CORPORATION OF CALIFORNIA 'APPARATUS FOR PUMPIN'G A PLURALIT'Y OF W'ELLS 1928. Serial No. 290,410.

Our invention relates to the pumping of wells, and articularly to a method of and apparatus or pumping oil wells by means of a gas supplied to the well under pressure. This application is a division of our application entitled Method of and apparatus for -pumping oil wells, Serial No. 204,999, vfiled Ju1y 11, 1927.

The ordinary t pe of gas-lift well has'a bore extending rom the surface of the ground through the oil bearing sands. A casing isinserted in the bore to a depth just above the oil sands, and is cemented in place there in order to keep the waterrout of thev downward inside the oil string'. Normally the oil rises to equal levels inside the bore, the oil string, and the oil-delivery pipe. If,

however, the annular space between the oil` string and the oil-'delivery pipe is sealed oi and a lgas under pressure inserted therein, the oil level in this annular space will be lowered, due to this pressure, and the oil will rise to the surface of the ground through the oil-delivery pipe because of the pressure on the oil outside the oil-delivery pipe being greater than that inside the pipe.

Ordinarily inthe operation of such a gas- I lift pump the pressure is supplied continuously, thereby ordinarily causing a steady flow of oil from the up er end of the oildelivery pipe. We have ound it advantageous to supply this pressure intermittently. This lowers the average working pressure of the Welland thereby makes it much .easier for the oil to seep through thescreen pipe into the oil string from the surrounding oilf bearing sand. Furthermore, less gas 1s rea method of intermittently su plyingpres- 1 quired to raise the same amount of oilv intermittently than is required in steady-dow conditions.

It is an object of our invention to provide sure to a well pump or other evlce.

In thus intermittently supplying pressure,

we have found it advantageous to so connect a compressor or compressor plant that it may supply each of several wells with pressure durlng consecutive intervals of time. Not only does this manifest economies in permitting the installation of a central compressor plant, thus greatly decreasing installation and operating costs, but also provides a niaximum vo'lume of gas which can be `almost instantaneously supplied to any one of the different wells, thus causin a quick build-up of pressure in the well belng pumped at that particular time.

It is anobject of our invention to rovide a method of controlling the supply o a compressed gas to a series of wells.

In thus supplying a number of wells intermittentlywith a compressedl gas, we have found it valuable to control this intermittent supply from a central point.

It is an object of our invention to provide la method permitting a centrally located control for the pumping of several wells.

We prefer to use electrically operated lvalves controlled from a central switch. We

have found it advantageous to carefully time the supply of compressed gas to a given well in order to obtain the best efliciency in the pumping operation. Different wells reuire a shorter or longer charging period, and

t e intermittent switch used to control a supply of compressed gas must permit ready ad-4 justment of the length of time of charging of each individual well.

Still a further object of our invention is to provide a methody of pumping well's which comprises l so regulating the intermittent charges of compressed air as to achieve the best pumping eiciency.

Further objects and advantages will' be made evident in the following description.

In the drawingsin which we 'show a. pre-` fel-red form of our invention,

Fig. 1 is a schematic wiring diagram of the installation controlling six oil wells.

Fig. 24is a side elevational view of the intermittent switch of our4 invention.

Fig. 3 is a top view of the intermittent switch.

Fig. 4 is a sectional view taken along the line 4-4 of Fig. 3.

Fig. 5 is a vertical sectional view through the distributor of the invention taken along the line 5-5 of Fig. 3.

Fig. 6 is a partially sectioned view showing the governor of the intermittent switch.

Fig. 7 is a horizontal sectional view taken along the line 7-'7 of Fig. 2.

Fig. 8 diagrannnaticall shows the means of varying the speed o the intermittent switch.

Fig. 9 is a diagrammatic view of a main valve used in the invention.

Fig. 10 is a diagrammatic view of a relief valve used in the invention.

Figs. 2 to 8 inclusive show the intermittent switch 15 of the invention. This switch comprises a motor 16 which is supported on feet 17, and which has a frame-work 19 supporting a top plate 20. Vertically pivoted in the top plate 20, and supported at its lower end by a jewel bearing 22, is a vertical shaft 24 of the motor 16, which carries near its central portion a disc 25 secured thereto by a set screw 26. Between the disc 25 and the top plate 2O is a pair of laminated cores 27 carrying windings 28. Directly below each of the laminated cores 27 is a laminated core 30 carrying a winding 31. The windings 28 and 31 are suitably connected to a source of alter nating current, and set up eddy currents in the disc 25, which is supported between the cores 27 and 31, thus causing it to rotate about. its vertical axis. This is a well known type of induction-disc-motor such as is found in certain types of watt-hour meters, and in certain electrically driven phono raphs. The rate of rotation of the rotor o the motor isv controlled by a governor which will now be described.

Mounted on the shaft 24r below the disc 25 is a helical gear 35 which meshes with a worm 36 cut in a horizontal shaft 38 pivotally supported by bearings 39 and 40, as best shown in Fig. 6. Adapted to slide on the horizontal shaft 38 is a sleeve 42- which has a friction plate 43 and a hub 44 at its left end. l A similar hub 46 is formed integral with the right end of the horizontal shaft 38. Connecting the hubs 44 and 46 are fiat springs 48, three in number, each'supporting at its central point a weight 50. The weight-s 50 fly outward as the speed of the horizontal shaft 38 is increased, and thus pull the friction plate 43 to the right.

Adapted to frictionally engage the fric' tion plate 43 on its right-hand face, as shown in Fig. 6, is a brake 54 mounted on an arm 56, which arm is pivotally supported in the frame 19 by a bolt 58. As the brake 54 is moved to the right, pivoting about the bolt v 58, the tendency of the disc 25 is to rotate faster, its load being partially removed, thus allowing the weights 50 to move outward until they draw the friction plate 43 into engagement with the brake 54, at which time the speed of the disc 25 will be held constant.

The upper end of the vertical shaft 24 carries a worm 60 which engages a worm 70 gear 61 mounted on a horizontal shaft 62 which rotates a distance above the top plate 20 in brackets 64 and 65, as most clearly shown in Fig. 4. An annular groove 66 is cut in the top plate 20 to allow clearance 75 for the worm gear 61 to rotate, this rotation being transferred to the horizontal shaft 62 by means of a set screw 68. The left end of the horizontal shaft 62 carries a worm 70 which is meshed with a helical pinion 72 80 carried on a counter-turned portion 73 of a vertical shaft 74, as shown in Fig. 5.

This vertical shaft 74 passes centrally through a distributor 75 of the invention.

The distributor 75 is secured to the top plate 85 20 by screws 76 passing through a housing 77 made of .suitable insulating material. Screwed into the bottom of the housing 77, and surrounding the vertical shaft 74, is a bearing 79 provided with a stuffing box 80. 90

The stuffing boX 80 forms a liquidstight seal between the housing 77 and the vertical shaft Equally spaced around the shaft 74 are downward projecting sleeves 82, each holding Figs. 2 and 3. The counter-turned portion 73 of the vertical shaft 74 extendsthrough a cup portion 90 ofthe housing 77, and car- 105 ries a rotor 91 which has an insulating sleeve 92, as shown in Fig. 5. Surrounding the insulating sleeve 92 is a metallic sleeve 93 which carries a rotor-contact 95. This rotorcontact 95 rotates with the shaft 74, and in no so rotating comes consecutively into contact with a series of six stationary contact arms 97, each of which is mounted on the upper end of one ofthe contact sleeves 83.

The rotor-contact 95 "remains in contact 115 with each of the contact arms 97 for one-sixth, of a revolution of the vertical shaft, and iniy mediately on sliding past one contact arm immediately springs outward into contact with the succeeding contact arm. As the spring contact moves over ,this new contact arm its free end follows the contour of the arm and is pushed inward. Reaching the edge of this contact arm the free end of the spring contact quickly flies outward, breaking contact With the contact arm previously guiding it inward and making Contact with the succeeding arm. This operation is continued throughout each revolution of the vertical shaft 74.

A brush 98 is adapted to bear against the upper end of the metallic sleeve 93, being Secured to the insulated housing 77 by means of a terminal 99, as indicated best in Fig. 3. The cup portion 90 of the housing 77 may be filled with oil to a level indicated at 100. This oil will effectively stop any sparking that may occur as the spring contact 95 bizeaks contact with one of the contact arms 9 v Mounted on the lower end of the vertical shaft 74 is a collar 102 which supports six equally spaced screws 104 which are threaded radially inward toward the center of the shaft 74. The distance between the axis of the shaft 74 and a head 105 of each screw 104 can be varied by turning the screw 104. These screws are locked in place when completely adjusted by means of lock nuts 106, which screw onto the screws 104 and bear against the outer periphery of the sleeve 102.

The heads 105 of the screws 104 are adapted to consecutively engage a curved plate 107. The curved plate 107 has a foot 108 carrying a groove'109. Extending through the groove 109, and threaded into the arm 56, are two screws 110 for the purpose of clamping the curved plate 107 and the arm 56. By loosening the screws 110 the curved plate 107 may be moved in a direction parallel to the grooves 109, as shown in Fig. 8, for a purpose to be described later. A spring 112 is secured to the arm 56 and also to a point on the frame 19, and is for the purpose of holding the screw heads 105 of the screws 104 against the curved plate 107.

When the motor 16 1s energized, the rotation of the disc 25 is transferred to the vertical shaft 74 through the `r)reduction gears previously-described. As the shaft 74 rotates it carries with it the sleeve 102 and the screws 104 held therein. As the screws 104 rotate about the axis of the shaft 74, they consecutively contact the curved plate 107, causing the arm 56 to slowly oscillate about the pivot 58. It ferring to Fig. 8, the maximum counter-clockwise oscillating movement of the arm 56 caused by. one of the screws'104, is shown in full lines, and occurs when one of the screw heads touches the curved plate at a point -that is on the line of centers of the shaft 74 and the center of curvature of the v curved plate 107. As the shaft 40 is rotated in the direction of the arrow 115, the arm 56 rotates slightly in a clockwise direction until screwv head, the arm 56 will reach its maximum counter-clockwise swing, as indicated by the dotted lines 117 of Fig. 8, at the time screwed further into the sleeve 102, the averthat the screw head touches the line of centers between the axis ofthe shaft 74, and the center of curvature of the curvedplate 107. This oscillatingof the arm 56 around the point 58 causes the brake 54 to change its position relative to the frame of the machine, and thus allows the friction plate 43 of the governor to slowly oscillate in step with the oscillations of the arm 56. As the friction plate 43 thus moves side to side the speed of the motor 16 is `consequently increased or diminished, as the case may be, in step with the oscillations of the arm 56.

It should be clear that even if all the screw heads 105 were to be the same distance from the axis of rotation of the shaft 74, the arm 56 would still oscillate and the speed of the motor would still vary in step with these oscillations. When one of the screws 104 is age speed of the motor during the time this screw is in engagement with the curved plate 107 is slower than the average speed during the engagement of the other screws. Thus the length of time that a circuit is closed between the terminal 99 and any one ofthe binding posts-87 can be regulated by varying the distance between the screw head 105 in use with that particular contact and the axis of rotation of the shaft 74. Or, if the Whole series of times of contact is to be lengthened or shortened simultaneously, the screws 110 are loosened and the curved plate 107 moved respectively toward or away from the axis of rotation of the shaft 7 4.

The timingbetween the distributor and the speed control mechanism can be varied by slightly rotating the sleeve 102 with respect to the shaft 7 4, but we prefer to so time the two that the circuit in the distributor is broken at the instant of maximum clockwise rotation of the arm 56; in other words, at the time two screw heads 105 are in contact with the arm 56 simultaneously.

Fig. 1 shows the application of the intermittent switch 15 to the pumping of six oil wells 124, each having a casing 125 and an oil string 126 extending therethrough into the oil below. Inside the oil string 125 is an oildelivery pipe 127 connected to a suitable storage. The top of each well is sealed as at 128.

A compressor plant 130 is adapted to supply a compressed gas to any one of the wells 124 through a header 131 with branch pipes 132 extending therefrom to eachoil string. In each branch pipe 132 -is inserted a main valve 135. These main valves 135 may be any type of valve which will open when a small current of electricity is passed through a suitable control winding.

In Fig. 9 we diagrammatically show such a main valve 135, which is operated by a solenoid 136, one terminal of which is connected to one of the binding posts 871 mounted on the intermittent switch 15, the other terminal being joined to a return conductor 139 which extends to the lower side of a low-tension power line 140, as shown in Fig. 1. The upper side of the line 140 is connected by means of a conductor 141 to the terminal 99 of the distributor 7 5. lVhen the rotor-contact 95 of the distributor 75 is in contact with the contact arm 97, which is connected to the solenoid of this particular main valve 135, current Hows through this particular solenoid 136. When the solenoid 136 is energized, an armature 144 is pulled downward into its full line position shown in Fig. 9. yThis armature pivots at 145 and pi'votally carries a rod 146 at its free end 147. The rod 146 extends through a pilot valve 148, which has a chamber 149 which communicates withithe branch pipe 132 through a pipe 150. Joining the chamber 149 with an upper chamber 151 is a vertical channel 152. At the junction of the vertical channel 152 and the chambers 149 and 150 are upper and lower valve seats 153 and 154. Adapted to close the upper seat 153 is a hall 156 mounted on the rod 146. A ball 158 secured to the lower end of the rod 146 is adapted to engage the lower seat 154 when the armature 144 is in its dotted line position.

A pipe 160 communicates between the vertical channel 152 and a chamber' 161 of a balanced valve 162. 1n the chamber 161 is a piston 163 which carries a rod 164. When the piston 163 is in its upper position, the balanced valve 162 is closed. When moved to a lower position, the piston 163v is adapted to onen the valve 162. The pilot valve 148 is so designed that when the solenoid 136 is energized.. thus moving the armature 144 into its full line position, the ball 156 seats in the upper seat 153, thus closing the upper end of the channel 152, while the ball 158 is positioned a distance below the lower seat 154 of the chazmel 152. This allows the high pressure ga.: to dow from the branch pipe 132 into the chamber' 149 through the pipe 150. This gas moves upward in the channel 152 and reaches the chamber 161 of the balanced valve through the pipe 160. This pressure transmitted to the chamber 161 forces the t piston 163 down. thus opening the valve.

When the circuit through the solenoid winding is broken, 'the armature 144 is moved into its dotted line position 168 by means of a spring 169 which pushes upward on the ball 158 at all times. this spring action being counteracted by the pull of the solenoid 136 when current is going therethrough. When in its dotted line position 168. the armature 144 carries the rod 146 upward, thus moving the ball 156 away from the upper seat 153, and lthe hall 158 into Contact with the lower seat 154. This allows the gas in the chamber 161 to escape through the upper chamber 151 of the pilot valve 148, and also stops any further flow of gas from the branch pipe 132 through the pipe 150. The release of the pressure in the chamber 161 allows the piston 163 to rise, thus closing thebalanced valve 162 of the main valve 135.

Between each main valve 135 and its correspending oil string 126 is a check valve 175 which is adapted to allow a gas to fiow downward into the well 124, but to prevent any gas from returning through the main valve 135. Each of the solenoid windings 136 of the main valve 135 is connected to one of the binding posts 87 of the intermittent switch 15, he other terminal of these solenoid windings being connected to the wire 139.

The valve 135 of one of the wells 126, this well being No. 1 of Fig. 1, is ley-passed by a relief Valve 180. This relief valve is adapted to be operated by a solenoid 181. The relief valve 180 may be of any type that will remain closed during the passage of an electric current through the solenoid, Winding 181, but which will immediately open with the stoppage of the current through the solenoid winding.

Such a relief valve is shown diagrammatically in lfig. 10, having a valve stem 183, which opens and closes the relief valve 180, thus the stem is urged upward by a spring 184 which tends to keep the relief valve 180 open at all times. Holding the stem 183 down, is an arm 185, which is pivoted at 186 to the frame of the relief valve 180. The left end of the arm 185 is connected by a spring 190 to an armature 192, which is pivoted at 193 and which is operated on by the solenoid 181. `When current is passing through the solenoid 181, the armature 192 is held in its full line position, thus holding the spring 190 in a slot 194 at the free end o' the armature 192. This spring holds the arm 185 in its full line position, thus holding the stem 183 in a depressed position, and the relief valve 180 consequently closed.

Should the current in the solenoid 181 be interrupted for any `reason, the armature 192 will rise into its dotted line position, allowing the lower end of the spring 190 to slip from the slot 194, thus freeing the arm 185, which is immediately moved upward into its dotted line position due to the upward pressure of the stem 183. This immediately opens the relief valve 180.

@ne terminal of the solenoid 18.1 is connected by a wire 196 to the wire 141. The other terminal of the solenoid winding 181 is connected by a wire 197 to a blade 198 of a safety switch 200. The blade 198 is pivoted at 201 to an arm 202 attached to the header 131. The left end of the blade 198 is kept in contact with a switch clip 204 by means of a spring 203. The clip 204 is connected by a wire 205 to the lower conductor of the low tension line 140, as shown in Fig. 1. Tn normal operation current flows from the line through the wires 205, 197, 196 and fes 141, the switch blade 148, and the solenoid winding 181, thus holding the relief valve closed.

A pop valve 210 is attached to the free vend of the header l131. This pop valve has a piston 212 working in a cylinder 213 of the valve, this piston being held in the right end of the cylinder 213 by a spring 215. Should the pressure in the header 131 rise to a point where the force on the .right-hand side of the piston 212 would be greater than the force exerted by the spring 215, the piston would move leftward, thus uncovering an opening 217 in the walls of the cylinder 213.

A tube 218 is connected to the opening 217. Closing the mouth of the tube 218 is a plate 220, which is formed integral with the blade 198 of the safety switch 200. When the pressure in the cylinder 213 forces the piston leftward, thus uncovering the opening 217, the gas pressure is transmitted to the plate 220, thus instantly lowering the blade 198 into its dotted line position, and thus disconnecting the blade 198 and the switch clip 204. This breaks the circuit through the solenoid winding 181, thus opening the relief valve 180.

1n operating the apparatus shown in Fig. 1, the most economical length of time of charge for each well is determined. This will depend upon a number of facts including the depth of the well, the viscosity of the oil to be pumped, and the rate of seepage of the oil into the oil string 126, besides other factors. We have found that this period of time of charge varies reatly in different wells. Thus in well o. 1, the charging period might be four minutes, the well No. 2 five minutes, and the well No.3 five and one-half minutes, etc. The. average length of time is usually about five minutes. After determining this most economical charging eriod the intermittent switch 15 is so ad- ]usted that the gas will be supplied to each v well for the required length of time. This adjustment is made by varying the distance between the screw heads 105 and the axis of rotation of the shaft 74, as previously.v described.

' When thus set and the .compressor plant started, a circuit will be closed from the line 140 through the wire 141, and through the distributor' 75, the current being then conducted to one of the solenoid windings 136 of one of the main valves 135, returning to the line 140 through the conductor 139. Thisy current energizes the solenoid 136 and holds the main valve 135 of this particular well open for the length of time required for most economical operation. When vthis length of time has elapsed, the rotor-contact 95 springs into engagement with the next contact arm 97, thus breaking the circuit through the first solenoid 136, and immediately makiga new circuit through-the succeeding solenoid winding. This ystoppage, of current through the l bringing this pressure being allowed to work on the surface of the oil in the well, forcing it upward through the oil-delivery pipe 127to a. suitable storage. 1t should thus be apparent that only one of the wells is receiving gas from the compressor plant at any instant of time, and that the closing of one main valve vis immediately followed by the opening of the succeeding main valve, thus never allowing the pressure in the header 131 to 'build up a dangerous values.

Should a main valve fail to open for any reason, such as mechanical failure or the electricity being cut off, it is apparent that the ressure in the header 131 will build up very ast. When this pressure reaches a value o from three hundred to four hundred pounds per square inch, depending upon the setting .of the pop valve 210, this pop valve opens,

allowing the pressure to e exerted on the plate 220 of the blade 198 o the safety switch 200. This opens the circuit which has previously been completed through the solenoid winding 181 of4 the relief valve 180. This stoppage of current through the solenoid winding 181 immediately opens the relief valve 180, thus allowing the compressor in the compressor plant 130 to discharge into one of the wells, in this case the well No. 1 of Fig. 1. The relief valve 180 is automatically closed when the pop valve 210 closes and allows the spring 203 to pull the safety switch 200 closed, thus sending current through the solenoid 181.

The intermittent switch 15 is valuable, not `only in the capacity shown, but may be used in numerous other installations, such as sign lighting or in other circuits requiring intermittent control.

The application of this intermittent switch to a series of wells already on production does not require the building of a single compressor plant to supply all of the wells. the compressors of each well `already 1n use, may be connected together.

Our invention is not limited to the use of 'a unitary compressor plant. t-i advany tageous, however, to use such a unitary compressor plant, locating all of the main valves, the relief valve, and the pop valve in the compressor plant itself. The intermittent swltch 15 should also be located inside the plant, thus the lwhole operating mechanism within the control of a single operator. We have found it advantageous to use a recording pressure gaugew230y connecting ms/13W' Instead,

header 131, thus recording at all times the pressures supplied to the diierent wells. I [t is also advantageous to insert a pilot light 1n each of the wires leading from the binding posts 87 to the solenoids 136. These pilot lights will be lighted during the time that current is passing to the solenoid winding, and consequently during the time that the main valve to that well is open, indicating to the operator that the well is being charged.

We claim as our invention:

1. An automatic gas lift system for wells comprising, a gas header carrying a compressed gas, branch pipes communicating between said header and each of said wells, a valve in each of said branch pipes a means for electrically operating each of said valves,

a check valve between each of the first-named valves and its corresponding well to 'preyent the return of said gas from said wells, and an adjustable timer for consecutively and automatically closing a circuit through each of said means for electrically operating each of said valves, for a predetermined interval of time, whereby the pumping period of each well is predetermined and whereby a predetermined cycle of operation ,is maintained.

2. An automatic gas lift system for a plurality of wells comprising, a gas header carrying a compressed gas, branch pipes communicating between said header and each of said wells, a valve in each of said branch pipes, a means for electrically operating each of said valves, and an adjustable timer foraconsecutively and automatically closing a circuit through each of said means for electrically operating each of said valves, for a predetermined interval ottime, whereby the pumping period of each well is predetermined and whereby a predetermined cycle of operation is maintained.

3. An automatic gas lift system for wells comprising, a gas compressing means, a header for carrying said compressed gas, branch pipes communicating between dsaid header and each of said wells, an electrically operated valve in each of said branch pipes, a check valve in each branch pipe between said electrically operated valve and its corresponding well, an electric circuit for each of said electrically operated valves, an independent circuit contactor for each of said electric circuits, an electric motor for operating said circuit contactor, a governor for controlling the interval of time during which said circuit contactor energizes each of said electric circuits, and an adjustable means for independently regulating the governor for each contactor.

4. An automatic gas lift system for wells comprising, a gas compressing means, a header for carrying said compressed gas, branch pipes communicating between said header and each of said wells, an electrically operated valve in each o said branch pipes, an electric circuit for each of said electrically operated valves, an independent circuit contactor for each of said electric circuits, an electric motor for operating s aid circuit contactor, a governor for controlling the interval of time during which said circuit contactor energizes each of said electric circuits, and an adjustable means for independently regulating the governor for each contactor.

5. An automatic gas lift system for wells comprising, a gas compressing means, a header for carrying said compressed gas, branch pipes communicatin between said header and each of said wel s, an electrically operated valve in each of said branch pipes, an electric circuit for each of said electrically operated valves, a distributer in circuit with each of said electric circuits, an electric motor for operating said distributer, a governor for controlling the interval of time during which the said distributer completes one of said electric circuits, and an adjustable braking means for independently regulating said governor for each circuit.

6. automatic gas lift system for wells comprising, a gas compressing means, a header for carrying said` compressed as, a header for carrying said compressed gas ranch pipes` communicating between said header and each of, said wells, an electrically operated valve in each of said branch pipes, a checkvalve in each of said branch pipes between said electrically operated valvev and its corresponding well, an electric circuit for each of said electrically operated valves, and an independently adjustable means for consecutively closing said electric circuits for a predetermined interval of time whereby the pumping (period of each well is predetermmedl'y a justed, and whereby the cycles of operation are automatically maintained.

'automatic gas lift system for wells comprising, a gas compressing means, a header for carrying said compressed gas, a header for carrying said compressed gas branch pipes communicating i between said header and each of said wells, operated valve in each of said branch pipes, a check valve in each of said branch pipes an electrically between said electrically operated valve and its corresponding well, an electric circuit for each of said electrically operated valves, an independently adjustable means for consecutively closing said electric circuits for a predetermined interval of time whereby the pumpmg period ofeach well is predeterminedly adjusted, and whereby Athe cycles of operation are automatically maintained, and means for by-passing said compressed gas into one of said wellsshould the pressure of said gas in said header rise above. a predetermined pressure.

8. In combination with. an automatically operated series of gas lift wells, a safety device comprising, a gas header carrying a compressed gas, a valve communicating with said gas header, a discharge pipe from said valve, a movable closure normally closing said discharge pi e, a spring for normally holding said-mova le closure in its closed position, anelectric circuit, a switch member -included -in said electric circuit and carried by said movable closure, a branch pipe connecting said gas header and one of said series of gas lift (Wells, an operating valve and a check valve in said branch pipe, a relief valve communicating with said branch pipe so as to by-pass said operating Valve but above said check valve, an electric means included in said electric circuit for holding said relief valve in its closed position, and a spring arranged 'in said relief valve to open said relief valve when said electric circuit is broken.

ln testimony whereof, the said WILLIAM A. GAMMACK' has hereunto set his hand at Los Angeles, California, this 1l dayrof June,

1928, and the said DONALD G. KNOX has hereunto set his hand at Tulsa, Okla., this 26day of June, 1928.

WlLLlAM A. GAMMACK. DONALD G. KNOX. 

